Comparative efficacy of indigenous Azospirillum spp. from the Saurashtra region in enhancing the growth of wheat (Triticum aestivum L.)

Azospirillum has been extensively used as a bio fertilizer to improve soil nutrient levels for a variety of crops. This genus, recognized for its positive impact on plant growth, offers a promising alternative to synthetic chemical fertilizers in traditional agriculture. In this study, we examined the potential of Azospirillum isolates from wheat fields in the Saurashtra region of Gujarat, India. Fifteen isolates were assessed for plant growth-promoting (PGP) traits, including the production of indole acetic acid (IAA), ammonia, phosphate solubilization, and siderophore production. All isolates were positive for IAA, ammonia and phosphate solubilization and 3 isolates were positive for siderophore production. The three most effective isolates showing close evolutionary relationships with Azospirillum sp. (SNP9), (SNP6), and (SNP3). A pot experiment was conducted to compare the effects of isolates SNP9, SNP6, and SNP3 on wheat plant growth against uninoculated controls. A 24-hour-old bacterial culture with a concentration of 108 CFU/mL was used for inoculation to evaluate significant growth parameter increases. The findings indicated significant growth enhancement in wheat plants inoculated with SNP9, moderate growth with SNP6, and minimal growth with SNP3 compared to uninoculated plants.